There are 30 protons and 39 neutrons in the nucleus.
This must me the isotope of an element with an atomic mass close to 69 u.
The only candidates are Zn and Ga.
Zn has a zinc-69 isotope with mass 68.926 u.
Ga has a gallium -69 isotope with mass 68.925 u.
The isotope is probably

.
It has 30 protons and 39 neutrons.
Answer:Hence, the bond length in HCl is 125 pm.
Explanation:
Bond length : It is an average distance between the nuclei of two bonded atoms in a molecule.
Also given that bond length is the distance between the centers of two bonded atoms. on the potential energy curve, the bond length is the inter-nuclear distance between the two atoms when the potential energy of the system reaches its lowest value. Beyond this if atoms come closer to each other then their will be repulsion between them.
So, the bond length between the Hydrogen and Chlorine atom in HCl molecule is :

Hence, the bond length in HCl is 125 pm.
Answer:
This question is incomplete, the complete question is:
Nancy and Hiyang are training for a race. They entered some of their training notes in a chart. Which information should be added to the chart in order find out who ran a greater distance?
The answer is C). the units used to measure distance each day
Explanation:
According to the question, Nancy and Hiyang are training for a race that involves them recording the distance they ran in a chart. Distance, as a quantity, is measured using different S.I units like metres, kilometers, miles, centimeters, etc.
However, in order to accurately discover whether Nancy or Hiyang ran a greater distance as recorded in their chart, the units used to measure distance each day must be included. This is because the unit of a quantity determines how big or small it is in comparison to another. For example, 20metres is not the same as 20centimetres.
If the unit they used in measuring their distance is not included, it will be impossible to tell what is being measured, talkless of who ran a greater distance
Answer:
about 29.5 days
Explanation:
it takes 27 days, 7 hours and 43 mins for our moon to complete a full orbit around the earth.